A Glimpse of Satellite Galaxies in the Milky Way with the 2.5 m Wide Field Survey Telescope (WFST): Boötes III and Draco
Abstract We carry out deep imaging of the Milky Way satellite galaxies, Boötes III and Draco, with the Wide Field Survey Telescope (WFST) as one pilot observing program to demonstrate the capability of WFST. Combining catalogs with PS1 DR2 and Gaia DR3, we derive proper motions for candidate member stars in these two satellite galaxies over a 12 yr time baseline, yielding uncertainties of ∼1.8 mas yr −1 at 21 mag and ∼3.0 mas yr −1 at 22 mag in the r band. The proper motions derived from bright and faint stars are consistent, indicating no significant variation in proper motion across stellar luminosity as these galaxies undergo tidal interactions with the Milky Way (MW). Meanwhile, we suggest that Boötes III represents the bound remnant of the progenitor galaxy that gave rise to the Styx stream, as evidenced by its elongated density profile and overdensity in both spatial and kinematic space. This is the first paper to use WFST to measure the proper motions of faint stars in MW satellite galaxies. More detailed analyses will be presented in forthcoming papers from the wide field survey program.
Authors
- Lulu Fan (ORCID: https://orcid.org/0000-0003-4200-4432)
- Xianzhong Zheng (ORCID: https://orcid.org/0000-0003-3728-9912)
- Ji-an Jiang (ORCID: https://orcid.org/0000-0002-9092-0593)
- Zhizheng Pan (ORCID: https://orcid.org/0000-0001-5662-8217)
- Yongquan Xue (ORCID: https://orcid.org/0000-0002-1935-8104)
- Jiang Chang (ORCID: https://orcid.org/0000-0001-7064-9321)
- Haibin Zhao (ORCID: https://orcid.org/0000-0001-9059-5623)
- Xu Kong (ORCID: https://orcid.org/0000-0002-7660-2273)
- Tianrui Sun (ORCID: https://orcid.org/0000-0003-1166-3814)
- Mingtao Liang (ORCID: https://orcid.org/0000-0001-8913-4811)
- Wentao Luo (ORCID: https://orcid.org/0000-0003-1297-6142)
- Zhen Wan (ORCID: https://orcid.org/0000-0002-3105-3821)
- Miaomiao Zhang (ORCID: https://orcid.org/0000-0002-6388-649X)
- W. Liu (ORCID: https://orcid.org/0000-0001-5549-8510)
- Zijian Lyu (ORCID: https://orcid.org/0009-0002-1587-5574)
- Man Qiao (ORCID: https://orcid.org/0009-0000-8142-323X)
- Tinggui Wang (ORCID: https://orcid.org/0000-0002-1517-6792)
- Ji Yang (ORCID: https://orcid.org/0000-0001-7768-7320)
- Y. Shu (ORCID: https://orcid.org/0000-0002-9063-698X)
- Shuang Liu (ORCID: https://orcid.org/0000-0002-0623-4022)
- Bin Li (ORCID: https://orcid.org/0000-0002-8903-3874)
- Jian Wang (ORCID: https://orcid.org/0009-0001-0445-4750)
- Guoliang Li (ORCID: https://orcid.org/0000-0002-3880-4448)
- Run Wen (ORCID: https://orcid.org/0000-0002-8705-6327)
- Hong-Xin Zhang (ORCID: https://orcid.org/0000-0003-1632-2541)
- Hairen Wang (ORCID: https://orcid.org/0000-0002-4372-0759)
- Binyang Liu (ORCID: https://orcid.org/0000-0002-0561-7937)
- Jinlong Tang
- Han Qu (ORCID: https://orcid.org/0000-0002-6016-5152)
- Feng Li (ORCID: https://orcid.org/0000-0002-9884-1996)
- Zheng Lou
- Dazhi Yao
- Min Fang (ORCID: https://orcid.org/0000-0001-8060-1321)
- Yu Heng Zhang
- Hongfei Zhang (ORCID: https://orcid.org/0000-0002-1463-9070)
- Hao Liu (ORCID: https://orcid.org/0000-0002-2366-9554)
- Chao Yang (ORCID: https://orcid.org/0009-0001-4009-9573)
Institutions
- University of Science and Technology of China (CN)
- Shanghai Jiao Tong University (CN)
- Chinese Academy of Sciences (CN)
- National Institutes of Natural Sciences (JP)
- Purple Mountain Observatory (CN)
- Institute of Optics and Electronics, Chinese Academy of Sciences (CN)
- NSF NOIRLab (US)
- National Astronomical Observatory of Japan (JP)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-07-24
- DOI
- https://doi.org/10.3847/1538-4357/ade78e
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China